A 27-year-old realtor and landlord explains the 4 things to look for in a good investment property

Dana Bull and her husband bought their first home, a condo in
Salem, Massachusetts, just nine months after graduating college.

But after deciding they wanted to be in Boston instead, where
most of their friends were living at the time, they rented out
the condo and used the income to cover rent and expenses in
the city.

"[I]n our first two months of
being landlords we had a mouse problem and one of the guys put a
shot glass down the disposal, so we had our first taste of it
[then]," Bull, now a
realtor with Sotheby's International, told Business
Insider.

"But ultimately, we were like
'You know, it's frustrating to have to deal with the maintenance
and have this whole other thing that we have to worry about ...
but it's a lot easier than our full-time jobs, which are
extremely time-consuming and stressful ... so we started thinking, 'Hey, maybe there's
something here,' and that was really where it all
started."

Today, the couple earns passive income from their six homes and
18 apartments in Boston and the North Shore.

1. Projected income

If you're getting into real estate
investing, you're probably hoping to get a nice return. But at
the bare minimum, you want to cover that monthly mortgage
payment. So how much rent should you plan on charging? Bull
says she always goes by the 1%
rule.

"Basically ... if you are
buying a property for $400,000, your hope is to ultimately be
able to get $4,000 a month in rent. So that's where you get that
1%. You're buying for $400,000 and your monthly income is
$4,000," she said.

In some parts of the country,
where property is less expensive and rents are higher, she says
you may want to go by the 2% rule.

2. Current tenant situation

One of the first things to take note of at a potential investment
property is the tenant situation. You don't want buy
on a whim and get stuck in a nightmarish situation.

"What's going on ... Are they tenant at will? Are they under
market? Do they pay? Get some clarity around that," she said.
"Some of these properties, they get really bad in terms of
hoarders and just mis-managed, bad situations. So try to wrap
your head around what's going on there."

3. Overall condition

"It's impossible to find a perfect property," Bull says, so be
aware of what needs fixing and whether you're prepared to
shell out the money and time to get it done.

"A new roof? OK it's expensive, but it's not hard to do. It can
be done in a matter of a week or two," she
said. "Re-plumbing an entire house? That's a different
story."

4. Utilities

If you're looking at multifamily property, like an apartment
building or a duplex, you'll need to find out if the utility
systems, like water and electric, are separate for each unit or
lumped into one, she said.

You're in the clear if the systems are separate, but if they're
not, then you'll likely have to pay to separate them or foot the
bill every month for the whole building.